The present invention relates to spinning processes for forming polymeric fibers. The present invention also relates to colored polymeric fibers.
Acrylic and acrylic-containing polymeric fibers and other polymeric fibers are often colored with pigments to form colored fabrics. The ability of the fiber to retain the color of the pigment depends in part on the degree of incorporation of the pigment into the structure of the fiber. Wet and dry spinning are methods of forming acrylic and acrylic-containing polymeric fibers. In such methods, a poorly dispersed pigment in the spinning solution can produce fibers having poorly incorporated pigment. Without good dispersion of the pigment in the spinning solution, the pigment can plug up the filter screen and spinneret holes, and the fibers spun from the solution can break easily and exhibit poor color strength and color retention. Pigments that are not substantially compatible with a spinning solution can form non-stable dispersions, agglomerate, and/or clump together in the solution. Although mechanical mixing can be used to disperse a pigment in a spinning solution, the pigment will generally settle out of the solution and/or agglomerate if the pigment is not substantially compatible with the solution.
Thus, there is still a need for pigmented polymeric fibers which exhibit good, if not, excellent color retention and uniformity. There is also a need for a solution for spinning polymeric fibers, wherein the solution includes a pigment that can remain highly dispersed throughout the solution and become substantially incorporated into a fiber made from the solution. There is also a need for a spinning method for making polymeric fibers exhibiting uniform pigment distribution throughout the fibers, and high jetness when the pigment is a black pigment, like carbon black.
The present invention provides polymeric fibers which preferably exhibit uniformity of color throughout the fibers and have uniform weather and light-resistant color. The present invention also provides a solution for spinning polymeric fibers, wherein the solution includes a polymer and at least one pigment that remains highly or substantially dispersed throughout the solution, preferably over a period of one day or longer. The present invention also provides a polymeric fiber having a pigment which is substantially uniformly and homogeneously dispersed throughout the fiber. The present invention also provides spinning methods for making polymeric fibers. The fibers preferably exhibit a uniformly dispersed pigment distribution throughout the fibers.
The present invention relates in part to a method of making a polymeric fiber having incorporated therein a modified pigment, for example, a modified carbon black. The modified pigment has at least one organic group attached thereto. The attached organic group preferably provides the pigment with a polarity that enables the pigment to be highly dispersed in a spinning solution. Preferably, the polarity of the modified pigment is compatible with the polarity of the solvent such that the modified pigment can become highly or substantially dispersed in the spinning solution when combined together, and such that the modified pigment remains dispersed throughout the spinning solution, preferably for a period of time, for example, for 24 hours or more.
Preferred organic groups attached to the pigments for use in the present invention include groups containing a) at least one aromatic group or a C1-C12 alkyl group, optionally with b) at least one ionic group, at least one ionizable group, or a mixture of an ionic group and an ionizable group.
According to the present invention, methods are provided which include forming a spinning solution of at least one polymer, at least one modified pigment having at least one organic group attached thereto, and a solvent. The solvent substantially maintains the polymer in a dissolved state. The modified pigment preferably remains highly or substantially dispersed throughout the spinning solution.
Herein, the term xe2x80x9cacrylic-containing polymerxe2x80x9d refers to polymers formed from monomeric reactants including at least one monomeric acrylic structural unit. The acrylic-containing polymer may be a polyacrylic homopolymer containing repeating units of reacted acrylic monomers, or the polymer may be a polyacrylonitrile copolymer containing units of acrylonitrile monomers and units of polymerizable olefinic monomers. These acrylic-containing polymers also include xe2x80x9cacrylicxe2x80x9d and xe2x80x9cmodacrylic fibersxe2x80x9d as these terms are understood in the art. Other acrylic-containing homopolymers, copolymers, terpolymers, and oligomers may also be used according to the present invention so long as each contains at least one acrylic structural unit in the polymer.
According to the present invention, the polarity of the solvent used in the spinning solution and the polarity of the modified pigment are such that the modified pigment is maintained substantially dispersed throughout the solvent. In addition, as mentioned above, the solvent is capable of substantially maintaining the polymer in a dissolved state under the conditions used for spinning. Preferably, the polarity of the modified pigment is compatible with, or substantially close to or the same as, the polarity of the solvent used for dissolving the polymer.